Communication infrastructures suitable for mobile users have now become widely adopted. Whilst the primary driver has been mobile telephony using cellular radio infrastructures, the desire to implement mobile data-based services over these infrastructures, has led to the rapid development of data-capable bearer services across such infrastructures. This has opened up the possibility of many Internet-based services being available to mobile users.
By way of example, FIG. 1 shows one form of known communication infrastructure for mobile users providing both telephony and data-bearer services. In this example, a mobile entity 20, provided with a radio subsystem 22 and a phone subsystem 23, communicates with the fixed infrastructure of GSM PLMN (Public Land Mobile Network) 10 to provide basic voice telephony services. In addition, the mobile entity 20 includes a data-handling subsystem 25 interworking, via data interface 24, with the radio subsystem 22 for the transmission and reception of data over a data-capable bearer service provided by the PLMN; the data-capable bearer service enables the mobile entity 20 to communicate with a service system 40 connected to the public Internet 39. The data handling subsystem 25 supports an operating environment 26 in which applications run, the operating environment including an appropriate communications stack.
More particularly, the fixed infrastructure 10 of the GSM PLMN comprises one or more Base Station Subsystems (BSS) 11 and a Network and Switching Subsystem NSS 12. Each BSS 11 comprises a Base Station Controller (BSC) 14 controlling multiple Base Transceiver Stations (BTS) 13 each associated with a respective “cell” of the radio network. When active, the radio subsystem 22 of the mobile entity 20 communicates via a radio link with the BTS 13 of the cell in which the mobile entity is currently located. As regards the NSS 12, this comprises one or more Mobile Switching Centers (MSC) 15 together with other elements such as Visitor Location Registers 32 and Home Location Register 32.
When the mobile entity 20 is used to make a normal telephone call, a traffic circuit for carrying digitised voice is set up through the relevant BSS 11 to the NSS 12 which is then responsible for routing the call to the target phone (whether in the same PLMN or in another network).
With respect to data transmission to/from the mobile entity 20, in the present example three different data-capable bearer services are depicted though other possibilities exist. A first data-capable bearer service is available in the form of a Circuit Switched Data (CSD) service; in this case a full traffic circuit is used for carrying data and the MSC 32 routes the circuit to an InterWorking Function IWF 34 the precise nature of which depends on what is connected to the other side of the IWF. Thus, IWF could be configured to provide direct access to the public Internet 39 (that is, provide functionality similar to an IAP—Internet Access Provider IAP). Alternatively, the IWF could simply be a modem connecting to a PSTN; in this case, Internet access can be achieved by connection across the PSTN to a standard IAP.
A second, low bandwidth, data-capable bearer service is available through use of the Short Message Service that passes data carried in signalling channel slots to an SMS unit which can be arranged to provide connectivity to the public Internet 39.
A third data-capable bearer service is provided in the form of GPRS (General Packet Radio Service which enables IP (or X.25) packet data to be passed from the data handling system of the mobile entity 20, via the data interface 24, radio subsystem 21 and relevant BSS 11, to a GPRS network 17 of the PLMN 10 (and vice versa). The GPRS network 17 includes a SGSN (Serving GPRS Support Node) 18 interfacing BSC 14 with the network 17, and a GGSN (Gateway GPRS Support Node) interfacing the network 17 with an external network (in this example, the public Internet 39). Full details of GPRS can be found in the ETSI (European Telecommunications Standards Institute) GSM 03.60 specification. Using GPRS, the mobile entity 20 can exchange packet data via the BSS 11 and GPRS network 17 with entities connected to the public Internet 39.
Different data-capable bearer services to those described above may be provided, the described services being simply examples of what is possible.
The data connection between the PLMN 10 and the Internet 39 will generally be through a firewall 35 with proxy and/or gateway functionality. In FIG. 1, a service system 40 is shown connected to the Internet 40, this service system being accessible to the OS/application 26 running in the mobile entity by use of any of the data-capable bearer services described above. The data-capable bearer services could equally provide access to a service system that is within the domain of the PLMN operator or is connected to another public or private data network.
Whilst the above description has been given with reference to a PLMN based on GSM technology, it will be appreciated that many other cellular radio technologies exist and can typically provide the same type of functionality as described for the GSM PLMN 10.
Another technology for providing mobile data connectivity is that based on wireless LANs. Wireless LANs are gaining substantial acceptance as a means for providing mobile connectivity over a restricted area. FIG. 2 of the accompanying drawings illustrates the main components of a wireless LAN architecture consistent with the ANSI/IEEE Standard 802.11 (“Wireless LAN Medium Access Control and Physical Layer Specifications”). The FIG. 2 wireless LAN 44 comprises a distribution system 45 that serves to interconnect a number of access points (AP) 46 via a network. Each access point 46 connects with mobile stations (MS) 47 over a wireless medium to form a Basic Service Set 48 (BSS1 and BSS2). The totality of the basis service sets and the network that interconnects them is called an Extended Service Set (ESS). The wireless LAN may connect with other networks, including the internet, via a portal 49.
Wireless LANs can be used to provide connectivity over limited areas such as public spaces and publicly-accessible premises, both commercial and non-commercial. These limited areas of connectivity are often referred to as “hotspots” as they generally provide a much higher speed of data transfer to mobile devices than is available via other wireless systems of more general coverage such as the data-capable bearer services provided by cellular radio networks of the form illustrated in FIG. 1.
Whilst such connectivity “hotspots” are presently provided primarily by wireless LANs, other technologies can also be used to provide localised areas of high transfer rates (as compared to the surrounding environment) and as used herein the term “hotspot” is intended to be technology independent, merely indicating that improved data transfer rates are available in localised areas. For example, short-range wireless connectivity can be provided by a “Bluetooth” radio system.
It is an object of the present invention to help a user of a device with multiple wireless connectivity options, to appreciate the likely communication costs that will be incurred according to the quality of experience sought by the user.